Tuning the Pore Structure and Surface Properties of Carbon-Based Acid Catalysts for Liquid-Phase Reactions

Abstract

A series of sulfonic-acid-containing carbon catalysts were synthesized through the pyrolyzation of resorcinol–formaldehyde resins and subsequent sulfonation to investigate the tunability of their pore structure and surface properties. These catalysts were characterized by nitrogen gas adsorption, water vapor adsorption, elemental analysis, Boehm titration, and IR spectroscopy. Catalytic consequences of these properties were examined using two esterification reactions in which reactants of substantially different sizes (oleic acid vs acetic acid) are involved as well as the condensation of furfural with 2-methylfuran. The esterification of acetic acid with ethanol proceeded at nearly the same activity (TOF ∼ 0.02 s–1) for all synthesized catalysts regardless of the variation of their surface and pore properties. Poisoning experiments of acid groups in the synthesized catalysts with NaCl indicate that nearly all −SO3H groups are accessible to the reactants. However, the esterification of oleic acid with met...